| 摘要 |
PROBLEM TO BE SOLVED: To restrain deformation and improve durability by forming a seal ring of a carbon material, and providing a low pressure chamber in a fitting part through a communicating hole. SOLUTION: An annular seal ring 5 is formed of carbon material. In a space 6s surrounded with the inner surface 2a of a casing 2 and the inner surface of a pressing plate 3 fixed to the casing 2 by plural bolts 3a, the seal ring is disposed with a very small gap 21 formed between the inner peripheral surface 5a and the outer peripheral surface 1b of a rotating shaft 1. The seal ring 5 is pressed to the side surface of the casing 2 by a spring 4 between the side surface of the seal ring 5 and the inner surface of the pressing plate 3 in the axial direction of the rotating shaft 1. An O-ring 9 is fitted in a fitting part between the outer periphery of the seal ring 5 and the inner periphery of a holder 6, thereby performing gas sealing between a low pressure chamber 8 and the space 6s communicated with a high pressure chamber 30. A communicating hole communicates the low pressure chamber 8 with the low pressure chamber 31, and plural communicating holes are provided at equal spaces in the circumferential direction inside the seal ring 5.
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